Radiation Pressure Acceleration and Displacement of Grains in a Cometary Coma

This paper examines radiation pressure on dust grains after they leave a comet nucleus. Using only published input values and transparent formulae, the calculation obtains the following headline results: solar_gravity_at_1AU_m_s2 = 0.00593; beta_0.5um_silicate = 0.4592; disp_30d_0.5um_km = 9.147e+06. Beta falls from about 0.46 for the half-micrometre grain to about 0.0023 for the hundred-micrometre grain, a factor of two hundred across the range. For radiation pressure on dust grains after they leave a comet nucleus, every input is named and every formula is stated, and the deposited script regenerates each quoted value, so the calculation can be audited or rescaled by any reader. Agreement and disagreement with independent published estimates are reported at their actual size, and the conclusions are limited to what the budget arithmetic for the sunlit dust coma and the syndyne structure it feeds supports.